This section provides background information related to the present disclosure which is not necessarily prior art. In recent years, protocols related to vehicle based safety systems have been established for vehicle-to-infrastructure (V2I) communication and vehicle-to-vehicle (V2V) communication. Such protocols, in essence, establish a wireless communication system which may be referred to as a V2X system. For example, IEEE 802.11p and IEEE 1609 are standards that relate to wireless access in vehicular environments (WAVE).
The V2X system allows the exchange of data such as critical safety and operational data between vehicles and other external devices, such as stationary roadside terminals. An on-board equipment (OBE) disposed within the vehicle may then analyze the data received based on a series of predetermined algorithms to determine, for example, a possible collision threat. Under the V2X system, vehicles and stationary roadside terminals are required to communicate using dedicated short range communication (DSRC).
For V2V communication, vehicles may periodically transmit a message on a dedicated channel, such as a vehicle safety channel (VSC). The message may include information related to a subject vehicle's speed, breaking data, travel direction, and other suitable vehicle information. Other vehicles, which receive the message, may use the information to detect a possible collision with a neighboring vehicle.
For V2I communication, vehicles may receive WAVE service advertisements (WSA) via another dedicated channel, such as a control channel (CCH). Such WSA can be transmitted by the stationary roadside terminals. The WSA may contain a list of services that are available in the vicinity of the vehicle. For example, the WSA may pertain to services related to security certificates which can be downloaded, vehicle probe data which can be uploaded, restaurants, and other suitable services. The vehicle may then acquire such service by switching to yet another dedicated channel, such as a service channel (SCH). Specifically, the WSA message received on the CCH provides information regarding a SCH channel number at which the vehicle may acquire the desired service.
Under V2I communication, as shown in FIG. 8, the vehicle switches to the CCH during a designated CCH interval 134 and the SCH during a designated SCH interval 136. Both the CCH interval 134 and the SCH interval 136 are for preset time periods 138a and 138b, respectively, which may be determined by industry protocol/standards.
The VSC, the CCH, and the SCH are three different radio channels. To perform both V2V communication and V2I communication, the vehicle may utilize two DSRC radios, where one DSRC radio is dedicated for V2V communication and the other DSRC radio is dedicated for V2I communication.